The present invention relates to a multi-piece golf ball having at least a three-layer construction composed of a core, an intermediate layer, and a cover. More specifically, it relates to a golf ball having a reduced distance of travel compared with official balls in current use.
There are primarily two sets of Rules of Golf: one issued by the Royal and Ancient Golf Club of St. Andrews (R&A) and one issued by the United States Golf Association (USGA). Both are revised every few years to maintain the integrity of golf competition. Investigations on limiting the distance of golf balls in these Rules of Golf are slowly being carried out.
Of the golf balls that have been disclosed to date, a few are golf balls which intentionally limit the flight performance or are designed to travel a short distance. For example, JP-A 60-194967 describes a short distance golf ball which includes a foam-molded thermoplastic resin polymer and filler material, and has a density gradient that increases along the ball radius from the center to the surface of the ball.
However, although this golf ball does lower the ball initial velocity by decreasing the rebound resilience of the core material, the controllability and scuff resistance leave something to be desired.
U.S. Pat. No. 5,209,485 teaches a golf ball which has a low rebound and reduced distance. However, this ball has a high hardness and thus an unpleasant feel on impact.
U.S. Pat. No. 5,273,287 discloses a large-diameter golf ball having a diameter of 1.70 to 1.80 inches (43.18 to 45.72 mm), a weight of not more than 1.62 ounces, and a dimple surface coverage of at least 70% relative to the spherical surface of the ball. Yet, because the ball is larger than normal, it feels strange to the player. Also, the feel on impact has not been improved. Furthermore, manufacturing such large-diameter balls would require that major modifications be made to the design and production equipment for golf balls having a conventional ball diameter, and would adversely impact the productivity.
U.S. Pat. No. 6,248,028 (corresponding Japanese application: JP-A 11-104270), U.S. Pat. No. 6,663,507 (corresponding Japanese application: 2004-049913), U.S. Pat. No. 6,814,676 (corresponding Japanese application: 2003-190330) and U.S. Pat. No. 6,592,470 (corresponding Japanese application: 2002-315848) disclose multi-piece solid golf balls obtained by forming the cover of a thermoplastic polyurethane elastomer, and forming between the core and cover an intermediate layer of a thermoplastic polyester elastomer and a high-resilience ionomer. These golf balls have excellent overall ball properties, including not only flight, but also feel when played, controllability, spin stability, scuff resistance and durability to repeated impact. Yet, such multi-piece solid golf balls are all aimed primarily at achieving superior flight properties, and will often not be suitable for the limited-distance standardized balls which will be required in the future.